Overview
The ulnar nerve is one of the three main nerves that run down the arm. It travels through a narrow passage behind the bony bump on the inner side of your elbow (the medial epicondyle). Most people know that spot as the funny bone. The passage is called the cubital tunnel. Its roof is a tight fibrous band that stretches from the bony bump to the tip of the elbow (the olecranon). Each time you fully bend your elbow, the tunnel narrows and the nerve stretches. That is why symptoms build over time in people who sleep with folded arms, spend hours on the phone, or rest their elbows on hard surfaces.
When the nerve is squeezed for a long time, it stops working normally. The result is numbness and tingling in the ring and small fingers, the two fingers this nerve supplies. Many people also have aching pain along the inner elbow and a weaker grip and pinch. Over time, the small muscles between the thumb and index finger can visibly shrink. That muscle loss, called intrinsic atrophy, is a warning sign. Past a certain point, nerve damage does not fully reverse even after the pressure is relieved. That is why symptoms that persist or get worse should not wait.
Cubital tunnel release takes the pressure off the nerve at the elbow. The most common approach simply cuts the tight band that forms the roof of the tunnel. That turns the tunnel into an open channel. In some cases the nerve is also moved from behind the elbow to a new spot in front of it (called anterior transposition). Moving it removes the stretch-and-squeeze cycle altogether. The choice depends on how severe the compression is and whether the nerve tends to snap back and forth over the bony bump as the elbow bends.
How the Procedure Works
We open the fibrous roof of the cubital tunnel. Then we trace the ulnar nerve up and down the arm, releasing every band of tissue that squeezes it, from above the elbow down into the forearm. Releasing these bands without moving the nerve works well when the nerve sits quietly in its groove without snapping back and forth.
Sometimes the nerve slides forward over the bony bump each time you bend your elbow, which injures it with every stretch. If that happens, or if the tunnel cannot be opened enough by releasing alone, we move the nerve to the front of the elbow (transposition). There it sits under the muscle or just beneath the skin, following a straighter path without that snap. Small nerve branches cross the surgical field, and we identify them carefully. Cutting one can cause a painful area of numbness on the inner forearm.
When to Consider Cubital Tunnel Release
Cubital tunnel release is generally offered when symptoms, imaging, and a trial of non-operative care together point to surgery as the next step. The typical picture includes:
Ulnar neuropathy symptoms
Numbness and tingling in the ring and small fingers, weakness of grip or pinch, or intrinsic muscle wasting.
Failure of conservative care
Activity changes, night splinting to keep the elbow straight, and a course of therapy have not resolved the symptoms.
Confirmed compression
Nerve testing (electrodiagnostic studies) confirms the ulnar nerve is compressed at the elbow.
Treats: Cubital Tunnel Syndrome
Risks & Why We Still Recommend It
Every operation carries risk. This procedure is offered because the condition, when left untreated, can cause ongoing injury to the ulnar nerve, with worsening numbness in the small and ring fingers, weakness, and muscle wasting that does not fully recover. The decision to proceed weighs the risks of surgery against the limitations the condition places on daily function. Surgery does not remove risk; it addresses a problem that is otherwise progressive. Whether it is appropriate is determined for each patient in consultation with the surgeon.
The risks we discuss with you before cubital tunnel release include:
- bleeding and infection
- anesthesia risk
- persistent or recurrent symptoms (the ulnar nerve is less forgiving than the median)
- irritation of a small nerve across the inner forearm, which can cause a numb or sensitive patch of skin
- elbow stiffness
- if transposed: the nerve can kink at the new position
Surgery is appropriate when your symptoms, your exam, and your nerve-conduction study all confirm cubital tunnel syndrome that has not improved with conservative care. If that picture does not fit you, this operation is not offered.
Frequently Asked
questions we hear in clinicWhy are my ring and small fingers numb?
The ulnar nerve supplies those two fingers, and it runs through a narrow passage behind the bony bump on the inner elbow (the spot most people know as the funny bone). Each time you fully bend your elbow, the tunnel narrows and the nerve stretches. That is why symptoms build over time in people who sleep with folded arms, spend hours on the phone, or rest their elbows on hard surfaces.
Can I wait and see if it gets better on its own?
Symptoms that persist or get worse should not wait. When the nerve is squeezed for a long time, the small muscles between the thumb and index finger can visibly shrink, and past a certain point nerve damage does not fully reverse even after the pressure is relieved.
Do I have to try anything before surgery?
Yes. Surgery is generally offered after activity changes, night splinting to keep the elbow straight, and a course of therapy have not resolved the symptoms, and after nerve testing (electrodiagnostic studies) confirms the ulnar nerve is compressed at the elbow.
Will the nerve be moved, or just released?
The most common approach simply cuts the tight band that forms the roof of the tunnel, turning it into an open channel. If the nerve slides forward over the bony bump each time you bend the elbow, or the tunnel cannot be opened enough by releasing alone, the nerve is moved to the front of the elbow (anterior transposition), where it follows a straighter path.
Will my symptoms go away completely?
Not always. Persistent or recurrent symptoms are a known risk, and the ulnar nerve is less forgiving than the median nerve. Muscle wasting that has already developed does not fully recover, which is why we recommend not waiting once symptoms persist or worsen.
What are the main risks?
Bleeding and infection, anesthesia risk, persistent or recurrent symptoms, irritation of a small nerve across the inner forearm (a numb or sensitive patch of skin), elbow stiffness, and, if the nerve is transposed, kinking at the new position. The full picture is in the Risks section above.
Further Reading
External patient-education references and related OSI pages for additional background:
